Spark-plug for internal-combustion engines.



PATENTED AUG. 25, 1908.

C. THE. MEER. I SPARK PLUG FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED MAE.27,190B.

2 SHEETS-SHEET1.

ATTORNEY WITNESSES:

' PATENTED AUG. 25, 1908.

11. c. TER MEER.

SPARK PLUG IOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED MAB. 27,1908.

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HENRY G. TER MEER, OF SUMMIT, NEW JERSEY.

SPARK-PLUG FOR INTERNAL-COMBUSTION i Specification of Letters Patent.

Patented Aug. 26, 1908.

Application filed March 27, 1908. Serial m. 423,722.

To all whom it may concern:

Be it known that I, HENRY C. TER MEER,

' a citizen of the United States, and a resident of Summit, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Spark-Plugs for Internal-Combustion Engines, of which the following is a specification.

The invention relates to improvements in spark-plugs for internal combustion engines, and it consists in the novel features and combinations of parts hereinafter described, and particularly pointed out in the claims.

The objects of the invention are, generally speaking, to present a spark-plug of sim l1- fied construction and which will be highly eflicent and reliable in use.

A further object of the invention is to pre sent a spark-plug which may be readily taken apart for inspection, cleaning or repair without necessitatin or even rendering liable the breaking of pac ed joints between the insulators and their surrounding parts.

The invention will be fully understood from the detailed description hereinafterpresented,reference being had to the accompanying drawings, in which Figure 1 is a to view of a spark-plug constructed in accordance with and embodying my invention; Fig. 2 a side elevation of the same; Fig. 3 a vertical transverse section of the same on the dotted line A B of Fig. 1; Fig. 4 a detached top view of the up er outer insulator Fig. 5 a slde elevation of tile same Fig. 6 a detached top View of the lower outer insulator; Fig. 7 a side view of the same; Fig. 8 a detached top view ofthe bushing used to connect the up erand lower outer insulators; Fig. 9 a si e elevation of the same; Fig. 10 a detached top view of the binding ,post at the upper end of the plug; 11 a side elevation of the same; Fig. 12 a etached'top view of the binding post nut; Fig. 13 a side elevation of the same; Fig. 14 a detached top view; of the inner insulator and central electrode; Fig. 15' a side elevation, partly broken away, of the same, and Fig. 16 a side elevation, partly broken away, of a modified form of inner insulator carrying the-\central electrode.

In the. drawings, 1 designates the shell of the plug notshown, said shell having an exteriorly threaded cylindrical lower portion and an interiorly threaded upper portion. and being formed on the exterlor of its upper endwith tobe screwed into a cylinder-wall,

convenient tool to be used for screwing the shell into said wall.

The shell 1 has secured to its lower edge the electrode 10 of usual construction, and

a polygonal head to receive a wrench or other receives within its upper end the exteriorly threaded bushing 2 having apolygonal head for a wrench or other suitable a plying tool and an inwardly extended annu ar flange 20 for urposes to be hereinafter ex lained.

.T e outer insulators are num ered 3, 12 respectively and are centrally apertured through their length to receive the inner 1nsulator 7 containing the central electrode 8 which will preferably be a platinum wire 0.01

inch in diameter. The insulators 3, 12 will preferably be made of porcelain, lava or soapstone. and at-their facing sides are recessed, asat 21, about their central a ertures 22, 23 respectively tocooperate wit the. asbestos packing. 11 between said insulators and an annular projection or beading 24 on' thecylindrical, body having the central vertical aperture 22 and an exterior annular shoulder 25 to be engaged by the flange 20 on the bushing 2, as shown in Fig. 3. The upper end of the aperture-22 has converging walls, as at 26, to engage-the lower conical end of the binding post or terminal 4, which is inserted through said aperture 22 from the inner end of the insulator 3 and has a threaded end which projects above said insulator and receives a binding nut 5, the latter when screwed down on the up er end of said insulator firmly securing the post 4 in rigid position. The lower outer insulator ,12 1s in the form of a thick 'disk matching but se arated by the packing 11 from the lower on of the insulator 3, and this insulator 12 isfirmly Secured against said packing by an inwardly spun flange 14 on the lower edge of the bush-.

The inner insulator 7 ay be formed of any suitable materialbut w1ll preferably-consist of quartz or Jena glass fused around the central electrode 8, which extends entirely inner insulator 7 to secure the latter in firm position. The insulator 3 is an integral through said insulator and projects slightly above and below the same, a spark gap 9 be ing formed between theelec'trodes 8,10 and an auxiliary spark gap 6' being formed between-the, upper end of said electrode 8 and I that it is com aratively lo The insulator 7 is, of special character iii and small in diameter and as a tapered ower end, my

purpose being to improve the efficiency of the plug by reducing the surface of the insulator on which foreign matter, which causes leakage, can deposit to. a minimum. The lower tapered'end of the insulator 7 projectsbelow the shell 1, which affords a considerable chamber about said insulator above its lower end and below the lower .end of the insulator 12.

The inner insulator of Fig. 16 difiers from that shown in Fig.15 only in the formation of the tapered lower end thereof, the lower end of the insulator shown in Fig. 16 being tapered on concave lines, while that illustrated in Fig. 15 is tapered on straight lines.

One of the main advantages accomplished by my invention, especially by the design of the inner insulator 7, is toprevent the fouling 'of the surface of the insulator at its lower end. A deposit of soot on the insulator creates a comparatively low resistance path for the leakage of the current from one electrode to the other, diminishing the size of the ignition spark, which causes faultyigrution. As the carbon deposit on the insulator increases in thickness its resistance diminishes, causing more and more current to leak, until finally the spark ceases to ,pass between the s arking oints.

In accor anoe wit my invention I make the insulator 7 as small in diameter as possible, consistent with the requisite degree of strength, and thereby present the minimum surface on which carbon could be deposited. By making the insulator 7 of small diameter the cross-section (perpendicular to the path of the current) is reduced and hence the resistance of the deposit increased. The leakage current is thereby decreased, causmore cin'rent to jump the gap, with the result that a hotter spark is secured. On account of the small cross-section of the foreign substances de osited on the insulator 7, the resistance to t e current will be high and consequently heat will be produced, the greatest amount of heat being generated at the point of smallest cross-section near the end of the insulator. The design of the insulator is such that enough heat shall be produced at its end to burn off orvolatilize' any film of soot, oil or other foreign matter, a zone free'from the forelgn'matter being and assuring the reliable and efficient operation of the ln The sparl pi ug of my invention consists of few readily assembled parts of durable form and construction, and it is to be noted that the metal bushing 2' directly engages the shell 1 thereby forming a metal to metal joint by which the completecore is secured to said shell. The construction illustrated enables the removal of the core from the shell for the inspection, cleaninglor repair without necessitating or rendering 'able the breakin of packed joints between the insulators an their surrounding parts.

' What I claim as my invention and desire to secure by Letters Patent, is:

1. An electric ignition device comprising an outer insulator having a central opening throughout, an inner insulator of elongated form having within it an electrode and held within the opening of said outer insulator, the walls at the outer end of said opening converging, a binding post within the outer end of said opening and tapered to conform to the walls thereof, and a binding nut on the exposed threaded endof the post for securing the same in position; substantially as set forth. v

2. An electric ignition device comprisin an outer insulator having a central opening throughout, an inner insulator of elongated form having within it an electrode held with-- in the openingof said outer insulator, the walls at the-outer end of said opening converging, a binding post Within the outer end thus maintained around the central electrode of said opening and tapered to conform to the walls thereof, and'a binding nut on the exposed threaded end of the 0st forsecuring the same in position, a spar gap being left between the outerend of'said inner'insulator and its electrode and the inner end of said binding post; substantially as set forth.

3. An electric ignition device comprising outer matching insulators containing a central o ening and separated'at their facing ends y a packing, an inner insulator of elongated form held within said opening and having within it an electrode and formed on its exterior at a oint between the facing ends of said outer insulators with a shoulder, and means for securing the outer insulators together; substantially as set forth.

4. An electric ignition device comprising upper insulator having a shoulder to enga 0 the upper flange of said bushing; substantially as set forth.

' 5., An electric ignition device comprising outer matching insulatorscontaining a central 0 ening and separated at their facing ends y a. packing, an inner insulator of elongated form held within said opening and having within it an electrode and formed on its exterior at a oint between the facing ends of said outer insulators with a shoulder, a metal bushing for securing said upper and lower outer insulators and having an exterior screw thread, and a shell having an interior thread to receive said bushing and. an ex-- terior thread to be screwed into the wall ofa cylinder; substantially as set forth.

. 6. An electric ignition device comprising i I outermatching insulators containing acen- 2o ends tral o ening and separated at their facing y a packing, an inner insulator of elongatedfforrn held within said opening and;

, havingiwithin it an electrode and formed on its exterior at a point between the facing endsgof said outer insulators with a shoulder, a metal bushing for securingrsaid upper and lower outer insulators and having an exterior screwthrea'd, and a shell having an interior thread to receive said bushing, an exterior thread to be screwed into the wall of a cylinder and an inner. flange with a acking thereon to receive the lower edge 0 said bushing; substantially as set forth.

Signed at Summit, in the countyof Union,

and State of New Jersey, this twenty-sixth day of March A. D. 1908.

' Y HENRY C. MEER' Witnesses: 4

EUGENE C. PIiJRsON, EVERETT -T. SPINNING. 

